Hard to flight perfect

First we use pixhawk added into DJIF450,after little config (PID etc.) it can flight well.
But then we use a bigger frame than DJIM100(Symmetrical motor wheelbase:650mm) the wheelbase is 1300mm of mine.
It hard to flight well by manual mode.the pitch have a little shake and when brake the Multi-rotor in the pitch position the body came to very huge shake then stop going ahead.Also when there have some wind,the body become very shake.
i have changed the pid of pitchrate and others (also xyz) so ,is there any way i should think about? and other values i need to change?